Feb 17, 2005 1:23pm
Re: about 400TB of this design shipped to the Archive
You make a good point and I've often thought of something similar but it's not cost effective yet.
A good way to look at the equation is the delta per block device. Being vague about block device since sizes and type are many. The services you need to provide are access and power at a minimum and perhaps processing, more on that later.
Access ~ Megabits/Block Device, switching (level of oversubscrition on uplinks, if any), cabling, etc.
Power ~ Cabling, Power supplies, etc..
Cooling ~ putting thousands of these next to each other is more challenging that putting one on your desk.
A desktop PC version could be as cheap as a sempron board with CPU and a desktop powersupply and a linksys switch.
Stick it into a spreadsheet, play around..
The upshot in all this is processing. Once the scale is hundreds of nodes, and thus thousands of disks, the incremental cost, if any, of real CPU's, when compared to other models can be quite compelling.
Once you have all the variables plugged in, you'll notice the costs of things like having 4 100Mb ports vs. 1 1000Mb port. You'll also see how choosing between 4 Arm CPU's, 1 VIA or a Xeon affect your monthly power bill (don't forget about the AC.)
Even after all of that, some kind of erector set needs to suspend all this stuff (maybe in cases, maybe not) in some kind of room... keeping everything cool.